1 //===- DAGISelMatcherGen.cpp - Matcher generator --------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "DAGISelMatcher.h"
11 #include "CodeGenDAGPatterns.h"
13 #include "llvm/ADT/SmallVector.h"
14 #include "llvm/ADT/StringMap.h"
19 const PatternToMatch &Pattern;
20 const CodeGenDAGPatterns &CGP;
22 /// PatWithNoTypes - This is a clone of Pattern.getSrcPattern() that starts
23 /// out with all of the types removed. This allows us to insert type checks
24 /// as we scan the tree.
25 TreePatternNode *PatWithNoTypes;
27 /// VariableMap - A map from variable names ('$dst') to the recorded operand
28 /// number that they were captured as. These are biased by 1 to make
30 StringMap<unsigned> VariableMap;
31 unsigned NextRecordedOperandNo;
33 /// InputChains - This maintains the position in the recorded nodes array of
34 /// all of the recorded input chains.
35 SmallVector<unsigned, 2> InputChains;
37 /// Matcher - This is the top level of the generated matcher, the result.
38 MatcherNodeWithChild *Matcher;
40 /// CurPredicate - As we emit matcher nodes, this points to the latest check
41 /// which should have future checks stuck into its child position.
42 MatcherNodeWithChild *CurPredicate;
44 MatcherGen(const PatternToMatch &pattern, const CodeGenDAGPatterns &cgp);
47 delete PatWithNoTypes;
50 void EmitMatcherCode();
52 MatcherNodeWithChild *GetMatcher() const { return Matcher; }
53 MatcherNodeWithChild *GetCurPredicate() const { return CurPredicate; }
55 void AddMatcherNode(MatcherNodeWithChild *NewNode);
56 void InferPossibleTypes();
57 void EmitMatchCode(const TreePatternNode *N, TreePatternNode *NodeNoTypes);
58 void EmitLeafMatchCode(const TreePatternNode *N);
59 void EmitOperatorMatchCode(const TreePatternNode *N,
60 TreePatternNode *NodeNoTypes);
63 } // end anon namespace.
65 MatcherGen::MatcherGen(const PatternToMatch &pattern,
66 const CodeGenDAGPatterns &cgp)
67 : Pattern(pattern), CGP(cgp), NextRecordedOperandNo(0),
68 Matcher(0), CurPredicate(0) {
69 // We need to produce the matcher tree for the patterns source pattern. To do
70 // this we need to match the structure as well as the types. To do the type
71 // matching, we want to figure out the fewest number of type checks we need to
72 // emit. For example, if there is only one integer type supported by a
73 // target, there should be no type comparisons at all for integer patterns!
75 // To figure out the fewest number of type checks needed, clone the pattern,
76 // remove the types, then perform type inference on the pattern as a whole.
77 // If there are unresolved types, emit an explicit check for those types,
78 // apply the type to the tree, then rerun type inference. Iterate until all
79 // types are resolved.
81 PatWithNoTypes = Pattern.getSrcPattern()->clone();
82 PatWithNoTypes->RemoveAllTypes();
84 // If there are types that are manifestly known, infer them.
88 /// InferPossibleTypes - As we emit the pattern, we end up generating type
89 /// checks and applying them to the 'PatWithNoTypes' tree. As we do this, we
90 /// want to propagate implied types as far throughout the tree as possible so
91 /// that we avoid doing redundant type checks. This does the type propagation.
92 void MatcherGen::InferPossibleTypes() {
93 // TP - Get *SOME* tree pattern, we don't care which. It is only used for
94 // diagnostics, which we know are impossible at this point.
95 TreePattern &TP = *CGP.pf_begin()->second;
98 bool MadeChange = true;
100 MadeChange = PatWithNoTypes->ApplyTypeConstraints(TP,
101 true/*Ignore reg constraints*/);
103 errs() << "Type constraint application shouldn't fail!";
109 /// AddMatcherNode - Add a matcher node to the current graph we're building.
110 void MatcherGen::AddMatcherNode(MatcherNodeWithChild *NewNode) {
111 if (CurPredicate != 0)
112 CurPredicate->setChild(NewNode);
115 CurPredicate = NewNode;
120 /// EmitLeafMatchCode - Generate matching code for leaf nodes.
121 void MatcherGen::EmitLeafMatchCode(const TreePatternNode *N) {
122 assert(N->isLeaf() && "Not a leaf?");
123 // Direct match against an integer constant.
124 if (IntInit *II = dynamic_cast<IntInit*>(N->getLeafValue()))
125 return AddMatcherNode(new CheckIntegerMatcherNode(II->getValue()));
127 DefInit *DI = dynamic_cast<DefInit*>(N->getLeafValue());
129 errs() << "Unknown leaf kind: " << *DI << "\n";
133 Record *LeafRec = DI->getDef();
134 if (// Handle register references. Nothing to do here, they always match.
135 LeafRec->isSubClassOf("RegisterClass") ||
136 LeafRec->isSubClassOf("PointerLikeRegClass") ||
137 LeafRec->isSubClassOf("Register") ||
138 // Place holder for SRCVALUE nodes. Nothing to do here.
139 LeafRec->getName() == "srcvalue")
142 if (LeafRec->isSubClassOf("ValueType"))
143 return AddMatcherNode(new CheckValueTypeMatcherNode(LeafRec->getName()));
145 if (LeafRec->isSubClassOf("CondCode"))
146 return AddMatcherNode(new CheckCondCodeMatcherNode(LeafRec->getName()));
148 if (LeafRec->isSubClassOf("ComplexPattern")) {
149 // We can't model ComplexPattern uses that don't have their name taken yet.
150 // The OPC_CheckComplexPattern operation implicitly records the results.
151 if (N->getName().empty()) {
152 errs() << "We expect complex pattern uses to have names: " << *N << "\n";
156 // Handle complex pattern.
157 const ComplexPattern &CP = CGP.getComplexPattern(LeafRec);
158 return AddMatcherNode(new CheckComplexPatMatcherNode(CP));
161 errs() << "Unknown leaf kind: " << *N << "\n";
165 void MatcherGen::EmitOperatorMatchCode(const TreePatternNode *N,
166 TreePatternNode *NodeNoTypes) {
167 assert(!N->isLeaf() && "Not an operator?");
168 const SDNodeInfo &CInfo = CGP.getSDNodeInfo(N->getOperator());
170 // If this is an 'and R, 1234' where the operation is AND/OR and the RHS is
171 // a constant without a predicate fn that has more that one bit set, handle
172 // this as a special case. This is usually for targets that have special
173 // handling of certain large constants (e.g. alpha with it's 8/16/32-bit
174 // handling stuff). Using these instructions is often far more efficient
175 // than materializing the constant. Unfortunately, both the instcombiner
176 // and the dag combiner can often infer that bits are dead, and thus drop
177 // them from the mask in the dag. For example, it might turn 'AND X, 255'
178 // into 'AND X, 254' if it knows the low bit is set. Emit code that checks
180 if ((N->getOperator()->getName() == "and" ||
181 N->getOperator()->getName() == "or") &&
182 N->getChild(1)->isLeaf() && N->getChild(1)->getPredicateFns().empty()) {
183 if (IntInit *II = dynamic_cast<IntInit*>(N->getChild(1)->getLeafValue())) {
184 if (!isPowerOf2_32(II->getValue())) { // Don't bother with single bits.
185 if (N->getOperator()->getName() == "and")
186 AddMatcherNode(new CheckAndImmMatcherNode(II->getValue()));
188 AddMatcherNode(new CheckOrImmMatcherNode(II->getValue()));
190 // Match the LHS of the AND as appropriate.
191 AddMatcherNode(new MoveChildMatcherNode(0));
192 EmitMatchCode(N->getChild(0), NodeNoTypes->getChild(0));
193 AddMatcherNode(new MoveParentMatcherNode());
199 // Check that the current opcode lines up.
200 AddMatcherNode(new CheckOpcodeMatcherNode(CInfo.getEnumName()));
202 // If this node has a chain, then the chain is operand #0 is the SDNode, and
203 // the child numbers of the node are all offset by one.
205 if (N->NodeHasProperty(SDNPHasChain, CGP)) {
206 // FIXME: Not correct for complex patterns, they need to push their own
207 // *matched* input chain.
209 // Record the input chain, which is always input #0 of the SDNode.
210 AddMatcherNode(new MoveChildMatcherNode(0));
211 AddMatcherNode(new RecordMatcherNode("'" + N->getOperator()->getName() +
214 // Remember all of the input chains our pattern will match.
215 InputChains.push_back(NextRecordedOperandNo);
216 ++NextRecordedOperandNo;
217 AddMatcherNode(new MoveParentMatcherNode());
219 // If this is the second (e.g. indbr(load) or store(add(load))) or third
220 // input chain (e.g. (store (add (load, load))) from msp430) we need to make
221 // sure that folding the chain won't induce cycles in the DAG. This could
222 // happen if there were an intermediate node between the indbr and load, for
225 // FIXME: Emit "lastchain.getNode() == CurrentNode ||
226 // IsChainCompatible(lastchain.getNode(), CurrentNode)".
227 // Rename IsChainCompatible -> IsChainUnreachable, add comment about
230 // Don't look at the input chain when matching the tree pattern to the
234 // If this node is not the root and the subtree underneath it produces a
235 // chain, then the result of matching the node is also produce a chain.
236 // Beyond that, this means that we're also folding (at least) the root node
237 // into the node that produce the chain (for example, matching
238 // "(add reg, (load ptr))" as a add_with_memory on X86). This is
239 // problematic, if the 'reg' node also uses the load (say, its chain).
244 // | \ DAG's like cheese.
250 // It would be invalid to fold XX and LD. In this case, folding the two
251 // nodes together would induce a cycle in the DAG, making it a 'cyclic DAG'
252 // To prevent this, we emit a dynamic check for legality before allowing
253 // this to be folded.
255 const TreePatternNode *Root = Pattern.getSrcPattern();
256 if (N != Root) { // Not the root of the pattern.
257 // If there is a node between the root and this node, then we definitely
258 // need to emit the check.
259 bool NeedCheck = !Root->hasChild(N);
261 // If it *is* an immediate child of the root, we can still need a check if
262 // the root SDNode has multiple inputs. For us, this means that it is an
263 // intrinsic, has multiple operands, or has other inputs like chain or
266 const SDNodeInfo &PInfo = CGP.getSDNodeInfo(Root->getOperator());
268 Root->getOperator() == CGP.get_intrinsic_void_sdnode() ||
269 Root->getOperator() == CGP.get_intrinsic_w_chain_sdnode() ||
270 Root->getOperator() == CGP.get_intrinsic_wo_chain_sdnode() ||
271 PInfo.getNumOperands() > 1 ||
272 PInfo.hasProperty(SDNPHasChain) ||
273 PInfo.hasProperty(SDNPInFlag) ||
274 PInfo.hasProperty(SDNPOptInFlag);
278 AddMatcherNode(new CheckFoldableChainNodeMatcherNode());
282 for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i, ++OpNo) {
283 // Get the code suitable for matching this child. Move to the child, check
284 // it then move back to the parent.
285 AddMatcherNode(new MoveChildMatcherNode(OpNo));
286 EmitMatchCode(N->getChild(i), NodeNoTypes->getChild(i));
287 AddMatcherNode(new MoveParentMatcherNode());
292 void MatcherGen::EmitMatchCode(const TreePatternNode *N,
293 TreePatternNode *NodeNoTypes) {
294 // If N and NodeNoTypes don't agree on a type, then this is a case where we
295 // need to do a type check. Emit the check, apply the tyep to NodeNoTypes and
296 // reinfer any correlated types.
297 if (NodeNoTypes->getExtTypes() != N->getExtTypes()) {
298 AddMatcherNode(new CheckTypeMatcherNode(N->getTypeNum(0)));
299 NodeNoTypes->setTypes(N->getExtTypes());
300 InferPossibleTypes();
303 // If this node has a name associated with it, capture it in VariableMap. If
304 // we already saw this in the pattern, emit code to verify dagness.
305 if (!N->getName().empty()) {
306 unsigned &VarMapEntry = VariableMap[N->getName()];
307 if (VarMapEntry == 0) {
308 VarMapEntry = NextRecordedOperandNo+1;
310 unsigned NumRecorded;
312 // If this is a complex pattern, the match operation for it will
313 // implicitly record all of the outputs of it (which may be more than
315 if (const ComplexPattern *AM = N->getComplexPatternInfo(CGP)) {
316 // Record the right number of operands.
317 NumRecorded = AM->getNumOperands()-1;
319 if (AM->hasProperty(SDNPHasChain))
320 NumRecorded += 2; // Input and output chains.
322 // If it is a normal named node, we must emit a 'Record' opcode.
323 AddMatcherNode(new RecordMatcherNode("$" + N->getName()));
326 NextRecordedOperandNo += NumRecorded;
329 // If we get here, this is a second reference to a specific name. Since
330 // we already have checked that the first reference is valid, we don't
331 // have to recursively match it, just check that it's the same as the
332 // previously named thing.
333 AddMatcherNode(new CheckSameMatcherNode(VarMapEntry-1));
338 // If there are node predicates for this node, generate their checks.
339 for (unsigned i = 0, e = N->getPredicateFns().size(); i != e; ++i)
340 AddMatcherNode(new CheckPredicateMatcherNode(N->getPredicateFns()[i]));
343 EmitLeafMatchCode(N);
345 EmitOperatorMatchCode(N, NodeNoTypes);
348 void MatcherGen::EmitMatcherCode() {
349 // If the pattern has a predicate on it (e.g. only enabled when a subtarget
350 // feature is around, do the check).
351 if (!Pattern.getPredicateCheck().empty())
353 CheckPatternPredicateMatcherNode(Pattern.getPredicateCheck()));
355 // Emit the matcher for the pattern structure and types.
356 EmitMatchCode(Pattern.getSrcPattern(), PatWithNoTypes);
360 MatcherNode *llvm::ConvertPatternToMatcher(const PatternToMatch &Pattern,
361 const CodeGenDAGPatterns &CGP) {
362 MatcherGen Gen(Pattern, CGP);
364 // Generate the code for the matcher.
365 Gen.EmitMatcherCode();
367 // If the match succeeds, then we generate Pattern.
368 EmitNodeMatcherNode *Result = new EmitNodeMatcherNode(Pattern);
370 // Link it into the pattern.
371 if (MatcherNodeWithChild *Pred = Gen.GetCurPredicate()) {
372 Pred->setChild(Result);
373 return Gen.GetMatcher();
376 // Unconditional match.